In recent, as the demand of the energy increases, developments for the solar cell converting solar energy into electrical energy are proceeding.
Particularly, a CIGS-base solar cell, that is, p-n hetero junction device having a substrate structure including a glass substrate, a metal backside electrode layer, p-type CIGS-base light absorption layer, a high-resistant buffer layer, n-type transparent electrode layer and the like is widely used.
Further, to increase the efficiency of the solar cell, various researches are proceeding.